Damper



Feb; 26, 1952 A. w. scHAcH DAMPER Filed May 26, 1947 INVENTOR. A I heart W. Schach ATTORNEYS Patented Feb. 26, 1952 DAMPER AlberifW; Schaeh,.R;ockfrd, Ill., assignor to Barber-Gohnan Company, RockfortLJlL, a corporationloflllinois- Application May'26, 1947", Serial No. 750,616-

4: Claims. 12

This invention relates to' a" damper for" regthe general object is "to; provide a damper which isadapted for controlling theflow ofiain'under relatively high pressure; and which avoids the creation of any substantial noise as the damper approaches closed'position.

A more detailed object is to provide a damper in which the air flow is adjusted by relative movement between two sets of vanes; both, presenting air foil cros sections in all'degrees of opening of the damper..

Other objects and'advant'ages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in'which .ulating the flow of air through a-passage, and" I Figure 1 is across-sectional view of an'airduct';

equipped with a damper embodying the novel features of the present invention.

Fig. 2 is a cross section taken along the line 2-2 of Fig. 1.

Fig. 3 is a cross section taken along the line 33 of Fi 2.

Fig. 4 is a perspective view of one of the damper vanes.

For purposes of illustration, the improved damper is shown in the drawings as a means for controlling the flow of air through a duct H branching off from a main supply duct [0. The damper is a self-contained unit mounted within a rectangular frame [2 received in and secured to walls of the branch duct and selectively adjustable by turning a knob IS on the outer end of an operating shaft [4 which projects through one wall of the frame and branch duct.

In the form shown, the damper comprises two separate sets I5 and [6 of vanes of air foil cross section mounted in staggered relation for movement of the vanes of one set edgewise into and out of the spaces intervening between the vanes of the other set to vary the width of such spaces and thereby control the flow of air through the duct I I. Herein, the vanes [5 are stationary each having its opposite ends secured by pins H to supporting plates I'I which are fixed to the frame 12 so that the vanes are held in uniformly spaced parallel relation with the space intervening between the thickest section of the vane being substantially equal to such thickness. To provide the desired air foil cross section, the opposite side surfaces [8 of each vane are substantially fiat and converge toward each other from the wider semicircular edge l9, substantially intersecting at the other thin edge the width of each vane being several times the thickness thereof. The outermost vanes of each set lie against the sides of the frame I2.

The vanes I'Gare offthesamecross section and similarly spaced apart inrparallela relation with their: tail portionssecured by pins 2| to the side plates:- 22: slidable. in; the frame. l2. Brackets 214 secured. toxthe. plates 22- carry spaced rollers- 23: engageable with the walls of the frame 12. so that the unitslidesreadilywithin the latter frame. The thicker edge portions of the vanes l6 project-.fromv the plates 22 andthe-ends of thevanes. I 5 are spaced from the frame l2: so that by: movementiof the-plates: 22-, the=vanes I6 may be: moved-in; betweenv the. vanes Is to therposition-:shown: in. phantom in, Fig; 2 in which; the thicker edges of the two sets of vanes liein a common plane and themovable vanes completely'filI the spaces intervening' between the stationary vanes l'5ztherebyg completely interrupting; the flow of air through the duct ll.

As the plates 22 and the vanes I6 are retracted from this position,.the spaces between the vanes 15 are widened progressively permitting a corresponding increase in the flow of air through the damper. Maximum opening of the damper is achieved when the vanes l6 reach the position shown in full in Fig. 2. In all degrees of opening of the damper, the vanes of both sets present so-called air foil cross sections to the passing air thereby avoiding turbulence in the latter and offering minimum resistance to the air flow. As a result, the damper is adapted to control the flow of air maintained at relatively high pressures.

It has been found that the noise incident to the flow of air through the damper may be substantially eliminated by providing shallow recesses 25 in opposite sides of the vanes [5 at the narrow edges thereof, the recesses extending edgewise and partially across the vanes. To permit the vanes l5 and [6 to be duplicates, similar recesses are formed on the movable vanes [6.

Various operating means may be provided for adjusting the frame 24 axially of the duct II to thereby vary the degree of damper opening. Herein the operating means comprises a gear 26 fast on the shaft I 4 which is journaled in bearings 21 on the frame l2 and projects through a slot 28 in one of the plates 22. This gear meshes I with a rack 29 secured to the inner side of the plate 22. Thus, by turning the knob l3, the gear. causes the rack to move back and forth along the stationary rack correspondingly moving the plates 22 carrying the vanes I6.

I claim as my invention:

1. A damper comprising two sets of spaced parallel-vanes of an air foil cross section having thick edges rounded to a contour substantially equal to a semicircle and flat sides tapering substantially to a point from the diameter of said semicircle, the width of each vane being several times its maximum thickness adjacent its thicker edge, and (means supporting the vanes of the respective sets in staggered relation and for relative edgewise movement in unison to bring the vanes of one set into the spaces between the vanes of the other set wherby to vary the effective area of the air passage through the two sets of vanes, the vanes of both of said sets being arranged with their wider edges facing in the same direction.

2. An air flow control damper comprising a plurality of uniformly spaced parallel vanes of air foil transverse cross section having thick edges rounded to an approximately semicircular contour and generally fiat sides tapering substantially to a point, the width of each vane being several times its maximum thickness, a second similarly arranged set of vanes of similar air foil cross section and substantially equal maximum thickness, and means supporting said second vanes for bodily edgewise movement in unison into and out of the space between said first vanes, said rounded edges of the vanes of both sets facing in the same direction and the vanes of each set being spaced apart distances substantially equal to the thickest parts of the vanes of the other set so as to effect a complete closure of said spaces when the rounded edges of all of the vanes are disposed substantially in a common plane.

3. A damper comprisingtwo sets of spaced parallel vanes of air foil cross section having sides tapering from a thick rounded edge to a thin edge, certain of said vanes being formed with laterally opening recesses spaced along opposite sides of said thin edges and extending partially across the width of said vanes, and means supporting the vanes of the respective sets in staggered relation for relative endwise movement in unison to bring the vanes of one set into the spaces between the vanes of the other set whereby to vary the effective area of the air passage through the two sets of vanes, all of the vanes being arranged with their thicker edges facing in the same direction.

4. A damper comprising two sets of spaced parallel vanes of air foil cross section, each having substantially flat sides tapering from a thick rounded edge to a thin edge, means supporting the vanes of one of said sets for bodily edgewise movement in unison into and out of the spaces between the vanes of the other set, certain of said vanes being formed with laterally opening recesses spaced in a staggered relation along opposite sides of the vanes at said thin edges and extending partially across the width of said vanes.

ALBERT W. SCHACH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,941,287 Weiskope Dec. 26, 1933 1,950,792 Green Mar. 13, 1934 2,082,335 Hart June 1, 1937 

